N-[substituted alkylidene]fused-bicycloalkylidene quinolinamines useful for enhancing the cholinergic function in a mammal

ABSTRACT

There are disclosed novel compounds having the formula, ##STR1## wherein, m is an integer of 0-3; 
     n is an integer of 1-4; 
     R 1  is hydrogen, alkyl, cycloalkyl, arylloweralkyl, aryl, naphthyl, furyl, thienyl, pyridinyl or pyrrolyl; each R 2  and R 3  are independently hydrogen, loweralkyl or arylloweralkyl, or alternatively R 2  and R 3  taken together form a methylene or ethylene bridge; 
     X is hydrogen, loweralkyl, cycloalkyl, loweralkoxy, halogen, hydroxy, nitro, trifluoromethyl, formyl, loweralkoxycarbonyl, arylcarbonyl, --SH, loweralkylthio, --NHCOR 4  or --NR 5  R 6 , R 4  being hydrogen or loweralkyl, and R 5  and R 6  being independently hydrogen, loweralkyl or cycloalkyl; 
     Y is CH 2 , CH═CH, O, S or NR 7 , R 7  being hydrogen, loweralkyl or arylloweralkyl; with the proviso that the number of said methylene or ethylene bridge shall not exceed 1 and that when Y is CH 2 , one and only one combination of R 2  and R 3  must constitute a methylene or ethylene bridge; 
     stereo, optical and geometrical isomers thereof, and pharmaceutically acceptable acid addition salts thereof, which are useful for enhancing memory.

This is a continuation-in-part of a co-pending prior application, Ser. No. 223,848, filed Jul. 25, 1988, which is a continuation-in-part of a prior application, Ser. No. 094,181 filed Sept. 8, 1987, now abandoned.

The present invention relates to novel compounds having the formula, ##STR2## wherein,

m is an integer of 0-3;

n is an integer of 1-4;

R₁ is hydrogen, alkyl, cycloalkyl, arylloweralkyl, aryl, naphthyl, furyl, thienyl, pyridinyl or pyrrolyl; each R₂ and R₃ are independently hydrogen, loweralkyl or aryllowralkyl, or alternatively R₂ and R₃ taken together form a methylene or ethylene bridge;

X is hydrogen, loweralkyl, cycloalkyl, loweralkoxy, halogen, hydroxy, nitro, trifluoromethyl, formyl, loweralkoxycarbonyl, arylcarbonyl, --SH, loweralkylthio, --NHCOR₄ or --NR₅ R₆, R₄ being hydrogen or loweralkyl, and R₅ and R₆ being independently hydrogen, loweralkyl or cycloalkyl;

Y is CH₂, CH═CH, O, S or NR₇, R₇ being hydrogen, loweralkyl or arylloweralkyl; with the proviso that the number of said methylene or ethylene bridge shall not exceed 1 and that when Y is CH₂, one an only one combination of R₂ and R₃ must constitute a methylene or ethylene bridge;

stereo, optical and geometrical isomers thereof, and pharmaceutically acceptable acid addition salts thereof, which are useful for enhancing memory.

Throughout the specification and the appended claims, a given chemical formula or name shall encompass all stereo and optical isomers thereof where such isomers exist, as well as pharmaceutically acceptable acid addition salts thereof and solvates thereof such as for instance hydrates.

The following definitions shall apply throughout the specification and appended claims.

Unless otherwise states or indicated, the term alkyl denotes a straight or branched alkyl group having from 1 to 18 carbon atoms. Examples of said alkyl include methyl, n-propyl, iso-butyl, heptyl, decyl, dodecyl, hexadecyl and octadecyl.

Unless otherwise stated or indicated, the term loweralkyl denotes a straight or branched alkyl group having from 1 to 6 carbon atoms. Examples of said loweralkyl include methyl, ethyl, n-propyl, iso-butyl, pentyl and hexyl.

Unless otherwise stated or indicated, the term cycloalkyl denotes a saturated ring containing 3 to 7 carbon atoms. Examples of said cycloalkyl include cyclopropyl, cyclohexyl and cycloheptyl.

Unless otherwise stated or indicated, the term halogen shall mean fluorine, chlorine, or bromine or iodine.

Unless otherwise stated or indicated, the term aryl shall mean an unsubstituted phenyl group, a phenyl group substituted with 1, 2 or 3 substituents each of which being independently loweralkyl, loweralkoxy, halogen, hydroxy, trifluormethyl, phenoxy or benzyloxy.

The phrase "each R₂ " appearing in the definition of group R₂ refers to the fact that when n is greater than 1, there are more than one R₂ group in the molecule, in which case they may or may not be the same. Similarly, the phrase "each R₃ " appearing in the definition of group R₃ refers to the fact that when m is greater than 1, there are more than one R₃ group in the molecule in which case they may or may not be the same. The groups R₂ and R₃ may combine so as to form a methylene or ethylene bridge in the molecule, but the number of such bridge is limited to 0 or 1.

The compounds of this invention can be prepared by utilizing the synthetic scheme described below.

SYNTHETIC SCHEME

A compound of formula II is allowed to react with an aldehyde of formula III to afford compound I, where the definitions of m, n, R₁, R₂, R₃, X and Y are the same as given above. Typically, this reaction is conducted in a suitable solvent such as benzene, toluene or xylene at a temperature of about 80°-150° C. in the presence of a base such as piperidine, morpholine, diethylamine or diisopropylamine. The starting compound II can be prepared, for instance, by utilizing synthetic schemes disclosed in U.S. patent application, Ser. Nos. 21,8,755, filed Jul. 8, 1988; 244,212, filed Sept. 24, 1988; and 171,103, filed Apr. 4, 1988, now U.S. Pat. No. 4,843,079. ##STR3##

The compounds of Formula I of the present invention are useful in the treatment of various memory dysfucntions characterized by decreased cholinergic function, such as Alzheimer's disease.

This utility is manifested by the ability of these compounds to inhibit the enzyme cholinesterase and thereby increase acetylcholine levels in the brain. Further, the compounds of this invention are in general less toxic and have a broader therapetuic window than heretofore known compounds such as tacrine and physostigmine, making them more therapeutically acceptable.

The ability to inhibit acetylcholinesterase was determined by the photometric method of Ellman et al., Biochem. Pharmacol. 7,88 (1961). Results of acetylcholinesterase inhibition for some of the compounds of this invention are presented in Table 1 along with those for reference compounds.

                  TABLE 1                                                          ______________________________________                                         Acetylcholinesterase Inhibition Assay                                                                 Acetylcholinesterase                                                           Inhibition                                              Compound               IC.sub.50 (molar)                                       ______________________________________                                         1,4-Methano-N-(phenylmethylene)-1,2,3,4-                                                              1.2 × 10.sup.-5                                   tetrahydro-9-acridinamine                                                      1,4-Methano-N-(phenylmethylene)-6-                                                                    2.2 × 10.sup.-5                                   trifluoromethyl-1,2,3,4-tetrahydro-9-                                          acridinamine                                                                   (Reference Compounds)                                                          Tacrine (9-amino-1,2,3,4-tetrahydroacridine)                                                          3.1 × 10.sup.-7                                   Physostigmine          6.0 × 10.sup.-9                                   ______________________________________                                    

This utility is further demonstrated by the ability of these compounds to restore cholinergically deficient memory in the Dark Avoidance Assay, where they are in general active over a broader dose range than heretofore known compounds, a distinct therapeutic advantage. In this assay mice are tested for their ability to remember an unpleasant stimulus for a period of twenty-four (24) hours. A mouse is placed in a chamber that contains a dark compartment; a strong incandescent light drives it to the dark compartment, where an electric shock is administered through metal plates on the floor. The animal is removed from the testing apparatus and tested again, twent-four (24) hours later, for the ability to remember the electric shock.

If scopolamine, an anticholinergic that is known to cause memory impairment, is administered before an animal's initial exposure to the test chamber, the animal re-enters the dark compartment shortly after being placed in the test chamber twenty-four (24) hours later. This effect of scopolamine is blocked by an active test compound, resulting in a greater interval before re-entry into the dark compartment.

The test results are expressed as the percent of a group of animals in which the effect of scopolamine is blocked, as manifested by an increased interval between being placed in the test chamber and re-entering the dark compartment. Results of Dark Avoidance Assay for a representative compound of this invention and physostigmine (reference compound) are presented in Table 2.

                  TABLE 2                                                          ______________________________________                                         Dark Avoidance Assay                                                                        Dose (mg/kg                                                                               % of Animals with                                                   of body    Scopolamin Induced                                     Compound     weight, s.c)                                                                              Memory Deficit Reversal                                ______________________________________                                         1,4-Methano-N-                                                                              0.31       27%                                                    (phenylmethylene)-                                                             1,2,3,4-tetrahydro-                                                            9-acridinamine                                                                 (Reference Compound)                                                           Physostigmine                                                                               0.31       20%                                                    ______________________________________                                    

Effective quantities of the compounds of the inentions may be administered to a patient by any of the various methods, for example, orally as in capsules or tablets, parenterally in the form of sterile solutions or suspensions, and in some cases intravenously in the form of sterile solutions, The free base final products, while effective themselves, may be formulated and administered in the form of their pharmaceutically acceptable acid addition salts for purposes of stability, convenience of crystallization, increased solubility and the like.

Acids useful for preparing the pharmaceutically acceptable acid addition salts of the invention include inorganic acids such as hydrochloric, hydrobromic, sulfuric, nitric, phosphoric and perchloric acids, as well as organic acids such as tartaric, citric, acetic, succinic, maleic, fumaric and oxalic acids.

The active compounds of the present invention may be orally administered, for example, with an inert diluent or with an edible carrier, or they may be enclosed in gelatin capsules, or they may be compressed into tablets. For the purpose of oral therapeutic administration, the active compounds of the invention may be incorporated with excipients and used in the form of tablets, troches, capsules, elixirs, suspensions, syrups, wafers, chewing gum and the like. These preparations should contain at least 0.5% of active compounds, but may be varies depending upon the particular form and may conveniently be between 4% to about 70% of the weight of the unit. The amount of active compound in such compositions is such that a suitable dosage will be obtained. Preferred compositions and preparations according to the present invention are prepared so that an oral dosage unit form contains between 1.0-300 milligrams of active compound.

The tablets, pills, capsules, troches and the like may also contain the following ingredients: a binder such as micro-crystalline cellulose, gum tragacanth or gelatin; an excipient such as starch or lactose, a disintegrating agents such as alginic acid, Primogel, cornstarch and the like; a lubricant such as magnesium stearate or Sterotex; a glidant such as collodial silicon dioxide; and a sweetening agent such as sucrose or saccharin may be added or a flavoring agent such as peppermint, methyl salicylate, or orange flavoring. When the dosage unit form is a capsule, it may contain, in additions to materials of the above type, a liquid carrier such as a fatty oil. Other dosage unit forms may contain other various materials which modify the physical form of the dosage unit, for example, as coatings. Thus tablets or pills may be coated with sugar, shellac, or other enteric coating agents. A syrup may contain, in addition to the active compounds, sucrose as a sweetening agent and certain preservatives, dyes, coloring and flavors. Materials used in preparing these various compositions should be pharmaceutically pure and non-toxic in the amounts used.

For the purpose of parenteral therapeutic administration, the active compounds of the invention may be incorporated into a solution or suspension. These preparations should contain at least 0.1% of active compound, but may be varied between 0.5 and about 30% of the weight thereof. The amount of active compound in such compositions is such that a suitable dosage will be obtained. Preferred compositions and preparatins according to the present inventions are prepared so that a parenteral dosage unit contains between 0.5 to 100 milligrams of active compound.

The solutions or suspensions may also include the following components: a sterile diluent such as water for injections, saline solution, fixed oils, polyethylene glycols, glycerine, propylene glycol or other synthetic solvents; antibacterial agents such as benzyl alcohol or sodium bisulfite; chelating agents such as ethylenediaminetetraacetic acid; buffers such as acetates, citrates or phosphates and agents for the adjustment of tonicity such as sodium chloride or dextrose. The parenteral preparations can be enclosed in disposable syringes or multiple dose vials made of glass or plastic.

Examples of the compounds of this invention include:

1,4-methano-6-methyl-N-(phenylmethylene)-1,2,3,4-tetrahydro-9-acridinamine;

1,4-methano-N-(phenylmethylene)-6-trifluoromethyl-1,2,3,4-tetrahydro-9-acridinamine;

N-(phenylmethylene)-3,4-dihydro-1H-thiopyrano[4,3-b]quinolin-10-amine;

N-ethylidene-3,4-dihydro-1H-thiopyrano[4,3-b]quinolin-10-amine;

N-decylidene-3,4-dihydro-1H-thiopyrano[4,3-b]quinolin-10-amine;

N-(phenylmethylene)-3,4-dihydro-1H-pyrano[4,3-b]quinolin-10-amine;

N-[(4-fluorophenyl)methylene]-3,4-dihydro-1H-pyrano[4,3-b]quinolin-10-amine

N-hexylidene-3,4-dihydro-1H-pyrano[4,3-b]quinolin-10-amine;

N-(phenylmethylene)-2,3-dihydrothieno[3,2-b]quinolin-9-amine;

N-[(2-thienyl)methyene]-2,3-dihydrothieno[3,2-b]quinolin-9-amine;

N-dodecylidene-2,3-dihydrothieno[3,2-b]quinolin-9-amine;

N-(phenylmethylene)-1,3-dihydrothieno[3,4-b]quinolin-9-amine;

N-[(4-pyridinyl)methylene]-1,3-dihydrothieno[3,4-b]quinolin-9-amine;

N-tetradecylidene-1,3-dihydrothieno[3,4-b]quinolin-9-amine;

1-phenylmethyl-N-(phenylmethylene)-2,3-dihydro-2H-pyrrolo[3,2-b]quinolin-9-amine;

N-(phenylmethylene)-2,3-dihydro-1H-pyrrolo[3,2-b]quinolin-9-amine;

2-phenylmethyl-N-(phenylmethylene)-1,3-dihydro-2H-pyrrolo[3,4-b]quinolin-9-amine;

N-(phenylmethylene)-1,3-dihydro-2H-pyrrolo[3,4-b]quinolin-9-amine;

1,4-methano-N-(phenylmethylene)-1,2,3,4-tetrahydro-9-acridinamine;

N-ethylidene-1,4-methano-1,2,3,4-tetrahydro-9-acridinamine;

N-hexadecylidene-1,4-methano-1,2,3,4-tetrahydro-9-acridinamine;

1,4-ethano-N-(phenylmethylene)-1,2,3,4-tetrahydro-9-acridinamine;

1,4-ethano-N-[(4-fluorophenyl)methylene]-1,2,3,4-tetrahydro-9-acridinamine;

N-decylidene-1,4-ethano-1,2,3,4-tetrahydro-9-acridinamine;

7-methyl-1,4-methano-N-pentylidene-1,2,3,4-tetrahydro-9-acridinamine;

1,4-methano-N-(4-methylpentylidene)-1,2,3,4-tetrahydro-9-acridinamine;

N-[(cyclopropyl)methylene]-1,4-methano-1,2,3,4-tetrahydro-9-acridinamine;

N-[(cyclopentyl)methylene]-1,4-methano-1,2,3,4-tetrahydro-9-acridinamine;

N-[(cyclohexyl)methylene]-1,4-ethano-1,2,3,4-tetrahydro-9-acridinamine;

1,4-ethano-N-[(4-fluorophenyl)methylene]-1,2,3,4-tetrahydro-9-acridinamine;

1,4-ethano-N-octylidene-1,2,3,4-tetrahydro-9-acridinamine; and

7-chloro-1,4-ethano-N-(phenylmethylene)-1,2,3,4-tetrahydro-9-acridinamine;

The following examples are presented in order to illustrate this invention.

EXAMPLE 1 1,4-Methano-1,2,3,4-tetrahydro-9-acridinamine

Anthranilonitrile (2.40 g) was mixed together with norcamphor (4.40 g) and then 4.0 g of freshly fused ZnCl₂ was added and the reaction mixture was heated at 120° C. After 1.5 hours it became so thick that it could not be stirred, so 10 ml of 1,2-dichloroethane was added and the reaction mixture was refluxed for 1 hour. At the end of this time, 40 ml of 10% NaOH was added and the mixture was stirred overnight. It was then extracted several times with 2-butanone which gave a crude product that was purified by flash chromatography (EtOAc, then 5% Et₂ NH/EtOAc) to give 3.04 g of foam. Recrystallization from CH₂ Cl₂ /pentane gave 2.30 g of analytically pure product, m.p. 186°-188°.

ANALYSIS: Calculated for C₁₄ H₁₄ N₂ : 79.96%C, 6.71%H, 13.33%N, Found: 79.85%C, 6.65%H, 13.13%N.

EXAMPLE 2 1,4-Methano-N-(phenylmethylene)-1,2,3,4-tetrahydro-9-acridinamine

1,4-Methano-1,2,3,4-tetrahydro-9-acridinamine (8.40 g) was refluxed in 300 ml of toluene that contained 7.0 g of morpholine and 6.4 g of benzaldehyde that had been freshly washed with aqueous K₂ CO₃. The reaction mixture was refluxed overnight and then concentrated and purified by flash chromatography (20% EtOAc/CH₂ Cl₂) to give 9.51 g of chromatographically pure product. Analytically pure material was obtained by recrystallization from benzene/pentane, m.p. 128°-130° C.

ANALYSIS: Calculated for C₂₁ H₁₈ N₂ : 84.53%C, 6.08%H, 9.39%N, Found: 84.49%C, 6.02%H, 9.31%N.

EXAMPLE 3 1,4-Methano-6-methyl-1,2,3,4-tetrahydro-9-acridinamine

A solution of 2-amino-4-methylbenzonitrile (16.0 g) and zinc chloride (24.7 g) in 70 ml of nitrobenzene was heated at 50° C. for 1hour. To this was added norcamphor (20.0 g) and the mixture was stirred at 130° C. for 3 hours. The reaction mixture was cooled and diluted with ether and the zinc complex was filtered. This complex was partitioned between aqueous NH₄ OH and 2-butanone (MEK) and the aqueous phase was extracted with MEK. The organics were washed with water, dried (saturated NaCl,MgSO₄) and concentrated to an oil which was triturated with ether to give 12.8 g of white powder, m.p. 159°-162° C. A 4.0 g portion was recrystallized from isopropyl ether to give 2.5 g of analytically pure white solid, m.p. 162°-164° C.

ANALYSIS: Calculated for C₁₅ H₁₆ N₂ : 80.32%C, 7.19%H, 12.49%N, Found: 80.29%C, 7.05%H, 12.52%N.

EXAMPLE 4 1,4-Methano-6-methyl-N-(phenylmethylene)-1,2,3,4-tetrahydro-9-acridinamine

A solution prepared from 1,4-methano-6-methyl-1,2,3,4-tetrahydro-9-acridinamine (8.6 g), benzaldehyde (6.3 g, freshly washed with K₂ CO₃ solution), morpholine (6.9 ml) and toluene (300 ml) was refluxed, with removal of water, for eighteen (18) hours. At this time, 6.3 g of benzaldehyde was added and reflux was continued for twenty-four (24) hours. The solvent was then removed in vacuo and the imine was purified via flash chromatography (DCM) to give 7.3 g of an organish solid, m.p. 144°-147° C. A 3.5 g portion was recrystallized from isopropyl ether to give 2.54 g of light yellow crystals, m.p. 149°-152° C.

ANALYSIS: Calculated for C₂₂ H₂₀ N₂ : 84.58%C, 6.45%H, 8.97%N, Found: 84.46%C, 6.42%H, 9.00%N.

EXAMPLE 5 1,4-Methano-1,2,3,4-tetrahydro-6-trifluoromethyl-9-acridinamine

To a solution of 2-amino-4-trifluoromethylbenzonitrile (12.8 g) in 50 ml of nitrobenzene was added freshly fused and pulverized ZnCl₂ (14.1 g). This was heated at 50° C. for 1 hour and to this mixture was added norcamphor (11.4 g). The reaction mixture was heated at 130° C. for 3 hours, after which it was cooled, diluted with ethyl ether and filtered. The resulting solid was partitioned between 2-butanone (MEK) and aqueous NH₄ OH and the aqueous portion was extracted with MEK. The combined organics were washed with water, dried (saturated NaCl, MgSO₄) and concentrated to a solid which was triturated with ether/hexane to give 10.3 g of a white powder, m.p. 174°-179° C. A 4.0 g portion was recrystallized from methanol/water to give 3.5 g of an analytically pure white powder, m.p. 175°-178° C.

ANALYSIS: Calculated for C₁₅ H₁₃ F₃ N₂ : 64.74%C, 4.71%H, 10.07%N, Found: 64.70%C, 4.88%H, 10.09%N.

EXAMPLE 6 1,4-Methano-N-(phenylmethylene)-6-trifluoromethyl-1,2,3,4-tetrahydro-9-acridinamine

A mixture prepared from 1,4-methano-1,2,3,4-tetrahydro-6-trifluoromethyl-9-acridinamine (7.65 g), benzaldehyde (4.4 g, freshly washed with K₂ CO₃), morpholine (4.8 ml) and toluene (300 ml) was refluxed with removal of water for eighteen (18) hours. At this point, an additional 4.4 g of benzaldehyde was added and reflux was continued for twenty-four (24) hours.

The reaction was then concentrated to a solid and the residue was chromatographed (DCM) to give 8.3 g of an orangish solid, m.p. 120°-126° C. A 4.07 g portion was recrystallized from cyclohexane to give 2.56 g of an off-white solid, m.p. 127°-130° C.

ANALYSIS: Calculated for C₂₂ H₁₇ F₃ N₂ : 72.12%C, 4.68%H, 7.65%N, Found: 72.15%C, 4.83%H, 7.61%N.

EXAMPLE 7 3,4-Dihydro-1H-thiopyrano[4,3]quinolin-10-amine

Tetrahydrothiopyran-4-one (10.0 g) was mixed with anthranilonitrile (5.08 g) and the mixture warmed at 60° C. until a homogeneous solution was obtained. Freshly fused ZnCl₂ (8.2 g) was then added portionwise and the temperature of the reaction mixture raised to 120° C. After two (2) hours it was cooled and distributed between 10% NaOH and 2-butanone. The organic phase was separated, dried and concentrated, and the crude product triturated with Et₂ O and then passed over a silica gel column (5% Et₃ N/ethyl acetate). The product-containing fractions were concentrated and the product recrystallized from toluene to give 3.66 g, m.p. 214°-216° C.

ANALYSIS: Calculated for C₁₂ H₁₂ N₂ S: 66.63%C, 5.59%H, 12.95%N, Found: 66.74%C, 5.71%H, 12.79%N.

EXAMPLE 8 N-(Phenylmethylene)-3,4-dihydrothiopyrano-1H-[4,3-b]quinolin-10-amine

3,4-Dihydrothiopyrano-1H-[4,3-b]quinolin-10-amine (8.64 g) was suspended in 300 ml of toluene to which morpholine (7.0 g) and benzaldehyde (freshly washed with aqueous K₂ CO₃ solution, 8.50 g) were then added. The reaction mixture was refluxed overnight with removal of water (Dean-Stark trap) and then concentrated and purified by flash chromatography (20% EtOAc/CH₂ Cl₂). The product-containing fractions were concentrated to give 7.30 g of chromatographically pure product, m.p. 171°-173° C. Analytically pure material was obtained by recrystallization from CH₂ Cl₂ /pentane, m.p. 175°-176° C.

ANALYSIS: Calculated for C₁₉ H₁₆ N₂ S: 74.96%C, 5.30%H, 9.20%N, Found: 74.97%C, 5.25%H, 9.18%N.

EXAMPLE 9 1,4-Dihydro-1,4-ethano-9-acridinamine

A mixture prepared from anthranilonitrile (4.18 g), freshly fused zinc chloride (7.2 g) and 15 ml of nitrobenzene was heated at 50° C. for 45 minutes. To the resulting suspension was added bicyclo[2.2.2]oct-2-en-5-one (6.5 g) and this was heated at 130° C. for 1.5 hours.

The reaction mixture was cooled and treated with ethyl ether, and the precipitate was filtered, rinsed with ether and then partitioned between 2-butanone (MEK) and aqueous NH₄ OH solution. The aqueous phase was extracted with MEK and the combined organics were washed with water and dried (saturated NaCl, MgSO₄). Removal of the solvents gave 5.7 g of an off-white powder which was recrystallized from methanol/water to give 4.76 g of an off-white solid, m.p. 218°-220° C. d.

ANALYSIS: Calculated for C₁₅ H₁₄ N₂ : 81.05%C, 6.35%H, 12.60%N, Found: 80.96%C, 6.34%H, 12.65%N.

EXAMPLE 10 1,4-Dihydro-1,4-ethano-N-(phenylmethylene)-9-acridinamine

A mixture of 1,4-dihydro-1,4-ethano-9-acridinamine (11.4 g), benzaldehyde (8.2 g, freshly washed with K₂ CO₃ solution) and morpholine (9.0 ml) in 350 ml toluene was refluxed with removal of water for eighteen (18) hours. An additional 6 g of benzaldehyde was added and reflux was continued for twelve (12) hours with removal of water.

The reaction mixture was concentrated, passed through a column of florisil (DCM) and the imine was purified via flash chromatography (DCM then 5% EtOAc/DCM) to give 13.4 g of an orangish solid. A 3.0 g portion was recrystallized from methanol/water to give 2.54 g of light yellow crystals, m.p. 178°-180° C.

ANALYSIS: Calculated for C₂₂ H₁₈ N₂ : 85.13%C, 5.85%H, 9.02%N, Found: 85.03%C, 6.05%H, 8.94%N. 

We claim:
 1. A compound of the formula ##STR4## wherein m is an integer of 1-3;n is an integer of 1-4; R₁ is hydrogen, alkyl, cycloalkyl, arylloweralkyl, aryl, naphthyl, furyl, thienyl, pyridinyl or pyrrolyl; each R₂ and R₃ is independently hydrogen, loweralkyl or arylloweralkyl, except that one and only one combination of R₂ and R₃ must constitute a methylene or ethylene bridge; X is hydrogen, loweralkyl, cycloalkyl, loweralkoxy, halogen, hydroxy, nitro, trifluoromethyl, formyl, loweralkylcarbonyl, arylcarbonyl, --SH, loweralkylthio, --NHCOR₄ or --NR₅ R₆, R₄ being hydrogen or loweralkyl, and R₅ and R₆ being independently hydrogen, loweralkyl or cycloalkyl; Y is CH₂, or CH═CH;a stereo, optical and geometrical isomer thereof, or a pharmaceutically acceptable acid addition salt thereof.
 2. The compound as defined in claim 1, which is 1,4-methano-N-(phenylmethylene)-1,2,3,4-tetrahydro-9-acridamine.
 3. The compound as defined in claim 1, which is 1,4-methano-6-methyl-N-(phenylmethylene)-1,2,3,4-tetrahydro-9-acridinamine.
 4. The compound as defined in claim 1, which is 1,4-methano-N-(phenylmethylene)-6-trifluoromethyl-1,2,3,4-tetrahydro-9-acridinamine.
 5. The compound as defined in claim 1, which is 1,4-dihydro-1,4-ethano-N-(phenylmethylene)-9-acridinamine.
 6. The compound as defined in claim 1, which is 7-methyl-1,4-methano-N-pentylidene-1,2,3,4-tetrahydro-9-acridinamine.
 7. The compound as defined in claim 1, which is N-hexylidene-1,4-methano-1,2,3,4-tetrahydro-9-acridinamine.
 8. The compound as defined in claim 1, which is 1,4-methano-N-(4-methylpentylidene)-1,2,3,4-tetrahydro-9-acridinamine.
 9. The compound as defined in claim 1, which is N-[(cyclopropyl)methylene]-1,4-methano-1,2,3,4-tetrahydro-9-acridinamine.
 10. The compound as defined in claim 1, which is N-[(cyclopentyl)methylene]-1,4-methano-1,2,3,4-tetrahydro-9-acridinamine.
 11. The compound as defined in claim 1, which is 1,4-ethano-N-(phenylmethylene)-1,2,3,4-tetrahydro-9-acridinamine.
 12. The compound as defined in claim 1, which is N-[(cyclohexyl)-methylene]-1,4-ethano-1,2,3,4-tetrahydro-9-acridinamine.
 13. The compound as defined in claim 1, which is 1,4-ethano-N-[(4-fluorophenyl)methylene]-1,2,3,4-tetrahydro-9-acridinamine.
 14. The compound as defined in claim 1, which is 1,4-ethano-N-octylidene-1,2,3,4-tetrahydro-9-acridinamine.
 15. The compound as defined in claim 1, which is 7-chloro-1,4-ethano-N-(phenylmethylene)-1,2,3,4-tetrahydro-9-acridinamine.
 16. A pharmaceutical composition for enhancing the cholinergic function in a mammal which comprises an effective amount of a compound as defined in claim 1 and a suitable carrier therefor.
 17. The pharmaceutical composition as defined in claim 16 which comprises 1,4-methano-N-(phenylmethylene)-1,2,3,4-tetrahydro-9-acridinamine.
 18. A method of increasing the cholinergic function in a mammal which comprises administering to the mammal an effective cholinergic function enhancing amount of a compound as defined in claim
 1. 19. The method as defined in claim 18, which comprises the administration of 1,4-methano-N-(phenylmethylene)-1,2,3,4-tetrahydro-9-acridinamine. 